1. Field of the Invention
The present invention discloses new antimicrobial compositions to control plant diseases and to prevent microbial spoilage of crops.
2. Description of Related Art
It is estimated that about 25% of the world crop production is lost due to microbial spoilage, of which spoilage by fungi is by far the most important cause. Not only from an economical point of view, but also from a humane point of view it is of great importance to prevent spoilage of food products. After all, in many parts of the world people suffer from hunger.
Success in combating plant and crop diseases and in reducing the damage they cause to yields and quality depends greatly on the timely application of fungicides. The prolonged and frequent use of many fungicides such as e.g. benzamidazoles has contributed to reduce their effectiveness thanks to the development of phenomena of resistance.
An important class of fungicides are the strobilurins. They were first sold in 1996. Sales of strobilurins and related compounds totaled about $ 1500 million in 2004 which representing over 20% of the global fungicide market. Strobilurins are used in for instance cereals, turf grass, grapevines, potatoes and fruit, nut and vegetable crops. The huge impact of the strobilurin family on agriculture is well-reflected by the current status of azoxystrobin, which is registered for use on more than 80 different crops in more than 70 countries, representing over $ 500 million sales in 2004. It has also been suggested to use azoxystrobin as an anti-mould agent for the preservation of foodstuff (see WO 02/00027). Although the strobilurin fungicides have shown activity against fungi (see WO 2007/104677, WO 2007/104669, U.S. Pat. No. 7,071,188; U.S. Pat. No. 7,098,170 and U.S. Pat. No. 7,807,714), spoilage problems still occur. Moreover, several studies have shown that more and more fungi acquire resistance against these fungicides (see Heaney et al., 2000; Sierotzki et al., 2000; Bartlett et al., 2002). Furthermore, some of the currently used strobilurins such as e.g. metominostrobin have the disadvantage of being dangerous for the health of exposed persons and the environment (see Tomlin, 2000).
For many decades, the polyene macrolide antimycotic natamycin has been used to prevent fungal growth on food products such as cheeses and sausages. This natural preservative, which is produced by fermentation using Streptomyces natalensis, is widely used throughout the world as a food preservative and has a long history of safe use in the food industry. It is very effective against all known food spoilage fungi. Although natamycin is applied for many years in e.g. the cheese industry, up to now development of resistant fungal species was never observed.
Consequently, it can be concluded that there is a severe need for more effective, more environmental friendly, lower-toxicity and less harmful antimicrobial compositions, e.g. antifungal compositions, for the treatment of fungal growth in and on plants and crops.